A method and device for preparing high-purity electronic-grade hydrogen chloride from hydrogen-rich hydrogen chloride raw gas

Abstract

The present invention discloses a method and equipment for preparing high-purity electronic-grade hydrogen chloride from hydrogen-rich hydrogen chloride raw gas, which includes the following steps: (1) removing water through a two-stage cryogenic refrigerator; (2) further removing water through adsorption in an adsorption tower; (3) rectifying, wherein the gas phase material at the top of the tower is non-condensable gas such as hydrogen and carbon dioxide, which is directly discharged into an alkali washing section; (4) the material is passed into a light component removal tower for further rectification, wherein the gas phase material at the top of the tower is hydrogen chloride gas containing C1 and C2, which is directly discharged into an alkali washing section, and the material at the bottom of the tower is circulated back to the light component removal tower through a dehydrogenation tower; (5) the material is passed into a heavy component removal tower for further rectification, wherein the bottom of the tower is hydrogen chloride liquid containing high-boiling impurities such as chlorine, which is directly discharged into an alkali washing section, and the gas phase at the top of the tower is extracted to obtain high-purity electronic-grade hydrogen chloride. The method reduces the load of the adsorption tower and increases the processing volume per unit time; the process is simple, the energy consumption is low, the recovery rate is high, and it is easy to stably prepare high-purity electronic-grade hydrogen chloride, which is conducive to improving the production scale and the yield rate.

Description

Technical Field

[0001] The invention belongs to the field of electronic gas preparation, and in particular relates to a method and equipment for preparing high-purity electronic-grade hydrogen chloride from hydrogen-rich hydrogen chloride raw gas. Background Art

[0002] Hydrogen chloride is an electronic gas, mainly used in the vapor phase polishing of single crystal silicon wafers, the etching of epitaxial bases and the production of cemented carbide in the process of semiconductor device manufacturing. With the development of the microelectronics industry towards large size, high integration, high uniformity and high integrity, the application demand of electronic grade hydrogen chloride in the vapor phase polishing of single crystal silicon and the etching of epitaxial bases is increasing. This requires not only that its purity reaches 6N grade or above, but also that the content of impurities such as total hydrocarbons (THC) and carbon oxides be reduced as much as possible.

[0003] Patent document CN110255501A discloses a method for preparing electronic grade high-purity hydrogen chloride, in which the by-product hydrogen chloride gas produced by the reaction of toluene with chlorine is purified to prepare high-purity hydrogen chloride. However, the hydrogen content in the by-product hydrogen chloride treated by this method is low, which is actually very different from the hydrogen chloride raw gas with a hydrogen content of more than 7% obtained by the mainstream synthesis method for preparing hydrogen chloride in my country's industry. The high content of hydrogen seriously affects the stability of the operation of the distillation tower, and the high-purity hydrogen chloride obtained can only reach the 5N5 grade.

[0004] Patent document CN105502295A discloses a method for purifying electronic-grade hydrogen chloride, in which electronic-grade hydrogen chloride is prepared by first distillation and then adsorption. However, the two-tower distillation scheme has a large reflux ratio and high energy consumption. At the same time, the post-adsorption dehydration is not only easy to corrode the distillation process, but the powdered adsorbent is easily entrained by the gas into the finished product storage tank or finished product cylinder. Summary of the invention

[0005] The first object of the present invention is to provide a method for preparing high-purity electronic grade hydrogen chloride from hydrogen-rich hydrogen chloride feed gas.

[0006] The second object of the present invention is to provide an apparatus used in the preparation method.

[0007] To achieve the first object, the technical solution adopted by the present invention is: a method for preparing high-purity electronic-grade hydrogen chloride from hydrogen-rich hydrogen chloride feed gas, comprising the following steps:

[0008] (1) The water content of the hydrogen-rich hydrogen chloride feed gas is controlled below 50 ppm through a two-stage cryogenic chiller;

[0009] (2) Control the water content in the hydrogen-rich hydrogen chloride feed gas to below 0.5 ppm through adsorption in an adsorption tower;

[0010] (3) The dehydrated raw gas is passed into a dehydrogenation tower for distillation. The gaseous materials at the top of the tower are non-condensable gases such as hydrogen and carbon dioxide, which are directly discharged into the alkali washing section. The optional operation includes passing the bottom materials from the light component removal tower into the dehydrogenation tower for distillation.

[0011] (4) The liquid phase material from the top of the dehydrogenation tower is passed into the light component removal tower for further distillation. The gas phase material from the top of the tower is the hydrogen chloride gas containing C1 and C2, which is directly discharged into the alkali washing section. The bottom material of the tower is circulated back to the light component removal tower through the dehydrogenation tower;

[0012] (5) The liquid phase material from the bottom of the dehydrogenation tower is passed into the de-heavy component tower for further distillation. The bottom of the tower is the hydrogen chloride liquid containing high-boiling impurities such as chlorine, which is directly discharged into the alkali washing section. The vapor phase at the top of the tower is extracted to obtain high-purity electronic grade hydrogen chloride. The product purity reaches 99.9999%.

[0013] The hydrogen-rich hydrogen chloride feed gas described in the present invention refers to hydrogen chloride gas with a hydrogen content exceeding 7%.

[0014] Preferably, in the two-stage cryogenic freezer, the outlet temperature of the first-stage cryogenic freezer is 0-10°C, the outlet temperature of the second-stage cryogenic freezer is -30--10°C, and the material flow rate is 0.5-3.0 Nm 3 / h.

[0015] Preferably, the adsorbent is alumina or molecular sieve, the pressure of the adsorption tower is 2.0~3.0MPag, and the material flow rate is 0.2~2.2Nm 3 / h.

[0016] Preferably, the dehydrogenation tower, the light component removal tower, and the heavy component removal tower are all pressurized, and the operating pressure and operating temperature of each tower are:

[0017] Dehydrogenation tower: tower top pressure is 2.2~2.8MPag, tower bottom pressure is 2.3~2.9MPag, tower top temperature is -7~4℃, tower bottom temperature is -6.5~4.5℃;

[0018] Light component removal tower: tower top pressure is 2.0~2.7MPag, tower bottom pressure is 2.1~2.8MPag, tower top temperature is -10~2℃, tower bottom temperature is -9~4℃;

[0019] Heavy component removal tower: tower top pressure is 2.2~2.5MPag, tower bottom pressure is 2.3~2.8MPag, tower top temperature is -5~0℃, tower bottom temperature is -4~1℃.

[0020] Preferably, in the dehydrogenation tower, the light component removal tower and the heavy component removal tower, the top condensers all adopt partial condensers, and the cooling medium is -25~-20°C chilled water.

[0021] Preferably, in the dehydrogenation tower condenser, the vapor phase fraction of the distilled material is 0.05-0.10.

[0022] Preferably, in the light component removal tower, the bottom extraction to feed ratio is 0.2-0.5.

[0023] To achieve the second purpose, the technical solution of the present invention is: an apparatus used in a method for preparing high-purity electronic-grade hydrogen chloride from hydrogen-rich hydrogen chloride feed gas, comprising a two-stage cryogenic refrigerator, a coolant collecting tank, an adsorption tower, a dehydrogenation tower, and a light component removal tower connected in sequence through pipelines, wherein the top of the coolant collecting tank is connected to the adsorption tower, and the bottom is connected to the alkali washing section; the kettle of the dehydrogenation tower is connected to the middle of the heavy component removal tower, and the bottom of the light component removal tower is connected to the kettle of the dehydrogenation tower; and each tower is provided with a condenser at the top and a reboiler at the bottom.

[0024] The two-stage cryocooler is two cryocoolers connected in series.

[0025] Preferably, the adsorption towers are provided in two numbers, connected in parallel and used alternately.

[0026] Preferably, the tail gas pipelines at the top of the dehydrogenation tower and the light component removal tower are connected to the alkali washing section.

[0027] Preferably, the heavy component discharge pipeline of the heavy component removal tower is connected to the alkali washing system.

[0028] Due to the application of the above technical scheme, the present invention has the following advantages compared with the prior art: the method for preparing high-purity electronic-grade hydrogen chloride from hydrogen-rich hydrogen chloride raw gas of the present invention adopts industrial hydrogen chloride as the raw material, introduces a two-stage deep cooling system, reduces the load of the adsorption tower, and increases the processing volume per unit time; firstly removes a large amount of hydrogen in the dehydrogenation tower to ensure the stability of the operation of the distillation tower, and then removes C1, C2 and residual hydrogen in the light component removal tower to ensure the purity of the product, and the bottom material of the light component removal tower is recycled back to the dehydrogenation tower to reduce the load of the distillation tower, while effectively reducing the technical difficulty of the process, and is easy to stably prepare high-purity electronic-grade hydrogen chloride, which is beneficial to improve the production scale and yield rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 The present invention is a process flow chart for preparing high-purity electronic grade hydrogen chloride from hydrogen-rich hydrogen chloride feed gas.

[0030] Among them: E101-first-stage cryogenic refrigerator, E102-second-stage cryogenic refrigerator, V101-coolant collection tank, T101-adsorption tower A, T102-adsorption tower B, T201-dehydrogenation tower, T202-light component removal tower, T203-heavy component removal tower, E103-dehydrogenation tower condenser, E104-dehydrogenation tower reboiler, E105-light component removal tower condenser, E106-light component removal tower reboiler, E107-heavy component removal tower condenser, E108-heavy component removal tower reboiler. DETAILED DESCRIPTION

[0031] Conclusion The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] like Figure 1 As shown, an apparatus for preparing high-purity electronic-grade hydrogen chloride from hydrogen-rich hydrogen chloride feed gas comprises a two-stage cryogenic refrigerator, a coolant collecting tank, an adsorption tower, a dehydrogenation tower, and a light component removal tower which are sequentially connected by pipelines, wherein the top of the coolant collecting tank is connected to the adsorption tower, and the bottom is connected to the alkali washing section; the kettle of the dehydrogenation tower is connected to the middle of the heavy component removal tower, and the bottom of the light component removal tower is connected to the kettle of the dehydrogenation tower; a condenser is provided at the top of each tower, and a reboiler is provided at the bottom of each tower.

[0033] The two-stage cryogenic refrigerator is two cryogenic refrigerators connected in series; the adsorption tower is set to two, connected in parallel and used alternately; the top tail gas pipelines of the dehydrogenation tower and the light component removal tower are connected to the alkali washing section; the heavy component discharge pipeline of the heavy component removal tower is connected to the alkali washing system.

[0034] A method for preparing high-purity electronic-grade hydrogen chloride from hydrogen-rich hydrogen chloride feed gas comprises the following steps:

[0035] (1) After the hydrogen-rich feed gas is compressed and filtered, it is passed into the primary cryogenic refrigerator E101 and the secondary cryogenic refrigerator E102, and then the gas-liquid separation is achieved through the coolant collection tank V101, wherein the water content in the gas phase does not exceed 50ppm;

[0036] (2) The raw gas from the coolant collection tank is passed from the bottom of the adsorption tower to the adsorption tower AT101 or the adsorption tower BT102 for further deep dehydration, and the moisture content of the raw gas discharged from the top of the adsorption tower does not exceed 0.5ppm;

[0037] (3) The deep dehydrated raw gas and the material from the light component removal tower are passed into the dehydrogenation tower for distillation. The gas phase materials at the top of the tower are non-condensable gases such as hydrogen and carbon dioxide, which are directly discharged into the alkali washing section;

[0038] (4) The liquid phase material from the top of the dehydrogenation tower is passed into the light component removal tower for further refining. The gas phase material from the top of the tower is the hydrogen chloride gas containing C1 and C2, which is directly discharged into the alkali washing section. The bottom material of the tower is recycled back to the dehydrogenation tower;

[0039] (5) The liquid phase material from the bottom of the dehydrogenation tower is passed into the de-heavy component tower for further refining. The bottom of the tower is the hydrogen chloride liquid containing high-boiling impurities such as chlorine, which is directly discharged into the alkali washing section, and electronic grade hydrogen chloride is obtained at the top of the tower. The product purity reaches 99.9999%.

[0040] In a preferred embodiment, in a two-stage cryogenic system, the outlet temperature of the first cryogenic freezer is 0-10°C, the outlet temperature of the second cryogenic freezer is -30--10°C, and the material flow rate is 0.5-3.0 Nm 3 / h.

[0041] In a preferred embodiment, the pressure of the adsorption tower is 2.0~3.0MPag, and the material flow rate is 0.2~2.2Nm 3 / h.

[0042] In a preferred embodiment, the dehydrogenation tower, the light component removal tower, and the heavy component removal tower are all operated under pressure.

[0043] The operating pressure and operating temperature of each distillation column are:

[0044] Dehydrogenation tower: tower top pressure is 2.2~2.8MPag, tower bottom pressure is 2.3~2.9MPag, tower top temperature is -7~4℃, tower bottom temperature is -6.5~4.5℃;

[0045] Light component removal tower: tower top pressure is 2.0~2.7MPag, tower bottom pressure is 2.1~2.8MPag, tower top temperature is -10~2℃, tower bottom temperature is -9~4℃;

[0046] Deheavy component tower: tower top pressure is 2.2~2.5MPag, tower bottom pressure is 2.3~2.8MPag, tower top temperature is -5~0℃, tower bottom temperature is -4~1℃.

[0047] In a preferred embodiment, in the dehydrogenation tower, the light component removal tower, and the heavy component removal tower, the top condenser is a partial condenser, and the cooling medium is -25~-20℃ chilled water;

[0048] In a preferred embodiment, in the dehydrogenation tower condenser, the vapor phase fraction of the distillate material is 0.05 to 0.10;

[0049] In a preferred embodiment, in the light component removal tower, the bottom extraction to feed ratio is 0.2 to 0.5;

[0050] In a preferred embodiment, in the heavy component removal tower, high-purity electronic-grade hydrogen chloride with a purity of 99.9999% is obtained by extracting the vapor phase from the top of the tower, and is sent to the canning section for packaging.

[0051] The hydrogen-rich raw gas used in the present invention is industrial-grade hydrogen chloride obtained by mixing and burning hydrogen and chlorine at high temperature in a synthesis furnace, and its indicators are shown in Table 1.

[0052] Table 1 Composition of industrial grade hydrogen chloride in a specific embodiment

[0053]

[0054] Example 1

[0055] The hydrogen-rich feed gas in Table 1 was adjusted to 1 Nm 3 The processing capacity of / h is pressurized to 3.2MPag by a compressor. After passing through the primary and secondary coolers, the outlet moisture content is detected to be 40ppm. After passing into the adsorption tower, the outlet moisture content is detected to be 0.5ppm. It is directly sent to the distillation section to prepare high-purity electronic grade hydrogen chloride.

[0056] Table 2 Operating conditions and product purity of Example 1

[0057]

[0058] Example 2

[0059] The hydrogen-rich feed gas in Table 1 was adjusted to 2.5 Nm 3 The processing capacity of / h is pressurized to 3.5MPag by a compressor. After passing through the primary and secondary coolers, the outlet moisture content is detected to be 46ppm. After passing through the adsorption tower, the outlet moisture content is detected to be 0.9ppm. It is directly sent to the distillation section to prepare high-purity electronic grade hydrogen chloride.

[0060] Table 3 Operating conditions and product purity of Example 2

[0061]

[0062] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing high-purity electronic grade hydrogen chloride from hydrogen-rich hydrogen chloride feed gas, comprising the following steps: (1) Control the water content of the hydrogen-rich hydrogen chloride feed gas to below 50 ppm through a two-stage cryogenic chiller; (2) controlling the water content in the hydrogen-rich hydrogen chloride feed gas to below 0.5 ppm by adsorption in an adsorption tower; (3) The dehydrated raw gas is passed into a dehydrogenation tower for distillation. The gas phase materials at the top of the tower are non-condensable gases such as hydrogen and carbon dioxide, which are directly discharged into the alkali washing section; the optional operation includes passing the bottom materials from the light component removal tower into the dehydrogenation tower for distillation; (4) The liquid phase material from the top of the dehydrogenation tower is passed into the light component removal tower for further distillation. The gas phase material at the top of the tower is the hydrogen chloride gas containing C1 and C2, which is directly discharged into the alkali washing section, and the bottom material is recycled back to the dehydrogenation tower; (5) The liquid phase material from the bottom of the dehydrogenation tower is passed into the de-heavy component tower for further distillation. The hydrogen chloride liquid containing high-boiling impurities such as chlorine gas in the bottom of the tower is directly discharged into the alkali washing section, and the vapor phase at the top of the tower is extracted to obtain high-purity electronic grade hydrogen chloride; In the two-stage cryogenic freezer, the outlet temperature of the first-stage cryogenic freezer is 0-10°C, the outlet temperature of the second-stage cryogenic freezer is -30--10°C, and the material flow rate is 0.5-3.0Nm 3 / h; The adsorbent in the adsorption tower is alumina or molecular sieve, the pressure of the adsorption tower is 2.0-3.0 MPag, and the material flow rate is 0.2-2.2 Nm 3 / h.

2. The method according to claim 1, characterized in that The dehydrogenation tower, light component removal tower, and heavy component removal tower are all pressurized operations. The operating pressure and operating temperature of each tower are: Dehydrogenation tower: tower top pressure is 2.2~2.8MPag, tower bottom pressure is 2.3~2.9MPag, tower top temperature is -7~4℃, tower bottom temperature is -6.5~4.5℃; Light component removal tower: tower top pressure is 2.0~2.7MPag, tower bottom pressure is 2.1~2.8MPag, tower top temperature is -10~2℃, tower bottom temperature is -9~4℃; Heavy component removal tower: tower top pressure is 2.2~2.5MPag, tower bottom pressure is 2.3~2.8MPag, tower top temperature is -5~0℃, tower bottom temperature is -4~1℃.

3. The method according to claim 1, characterized in that In the dehydrogenation tower, light component removal tower and heavy component removal tower, the top condenser adopts a partial condenser, and the cooling medium is -25 to -20℃ chilled water.

4. The method according to claim 1, characterized in that In the dehydrogenation tower condenser, the vapor phase fraction of the distilled material is 0.05-0.

10.

5. The method according to claim 1, characterized in that In the light component removal tower, the bottom extraction to feed ratio is 0.2 to 0.

5.

6. A method for preparing high-purity electronic-grade hydrogen chloride from hydrogen-rich hydrogen chloride feed gas, comprising a two-stage cryogenic refrigerator, a cooling liquid collecting tank, an adsorption tower, a dehydrogenation tower, and a light component removal tower, which are sequentially connected by pipelines, wherein the top of the cooling liquid collecting tank is connected to the adsorption tower, and the bottom is connected to the alkali washing section; the kettle of the dehydrogenation tower is connected to the middle of the heavy component removal tower, and the bottom of the light component removal tower is connected to the kettle of the dehydrogenation tower; and each tower is provided with a condenser at the top and a reboiler at the bottom.

7. The device according to claim 6, characterized in that The two-stage cryogenic refrigerator is two cryogenic refrigerators connected in series; the adsorption tower is provided in two, connected in parallel and used alternately.

8. The device according to claim 6, characterized in that The tail gas pipelines at the top of the dehydrogenation tower and the light component removal tower are connected to the alkali washing section; the heavy component discharge pipeline of the heavy component removal tower is connected to the alkali washing system.

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